JPS582233A - Manufacture of silica glass for optical fiber - Google Patents

Abstract

PURPOSE:To obtain homogeneous silica glass for an optical fiber at a high manufacturing speed by spraying sol prepared by hydrolyzing an alkyl silicate on a heating zone to form silica glass powder and by melting the powder with a flame. CONSTITUTION:An alkyl silicate such as tetramethyl silicate is mixed with an alcohol such as methanol in about 1:9 volume ratio, and to the mixture is optionally added >=1 kind of acid selected from phosphoric acid, stannic acid, plumbic acid, zincic acid, boric acid, titanic acid, aluminic acid and germanic acid or >=1 kind of ester of such acid as a dopant material. Water is then added to prepare sol 2 by hydrolysis. The sol 2 in a container 3 is fed into the core tube 11 of a furnace provided with a heating element 10 as sol droplets 9 together with a compressed gas 8 from a spray nozzle 6 through a transfer pipe 4. In the tube 11 the droplets 9 are converted into gel, forming silica glass powder 14 in a container 13. The powder 14 is heat treated at about 800- 1,500 deg.C and melted with a flame of oxygen and hydrogen to obtain transparent glass.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a highly manufacturable, easy-going, homogeneous, and transparent V-suit for a 7-eye machine.

Conventionally, S/IIs laser for optical Aipa, doped whips νxt in III#
No. 4114l! For example, silicon tetrachloride vapor and dopant may be added to the vapor and fl&l chloride dalma ink may be added to the raw material gas with oxygen and, if necessary, the vapor. BJ is held at both ends and abused
Heat it with a flame burner and blow it in to generate glass mold particles through flame hydrolysis or thermal oxidation.
Glass particles are blister produced by reaction to gas phase or hjI packaging, soOII! The great power of particles, the decomposition of a single flame (
1010~11.0) C) Sea~21661 at 0 event
m, 1m oxidation (loan ~ 1ioo℃) O case 10
On the other hand, glass mold particles are extremely small at 0~soon degrees, and flame or debris! Supplied into flame and melted, no bubbles
1. To produce doped silica glass at high speed.

It is known that the optimum size of the scissor particles is 10 to 100 pII@degrees.

The glass mold particles produced by the conventional O method are melted by an IIO flame or a gaseous flame, and are made into transparent vitrification (1400-1...℃).Residual bubbles era-
To obtain doped silica auras at a high production rate,
Prior to melting and transparent vitrification, the fine particles were heat-treated for 1 m (12 m)
60~1500℃) 1 grain 111e~1@epmli degree O! Must generate the next particle! ! There is a drawback that there is, but it is good.

The object of the invention is to overcome this drawback and by certain measures)
It is an object of the present invention to provide a method for producing silica glass for optical fibers at a high preparation rate by utilizing V silica-based O glass having a large particle size.

Overview of the present invention 1 The present invention's construction 111 for Hikari 7 eyelids hydrolyzes silicate in alkali to produce a sol-like **, and sprays a molten molten casing. Nozzle) Spray the glass powder into the heating zone to produce the glass powder, and then apply the glass powder to the flame or gun! Supply it into the flame and melt it.

It is characterized by transparent glass.

In the present invention, aluminum oxide (silicic acid 011 or complete alkyl ester) is used as the raw material for SS lath, and if desired, a dopant material (l/
As an additive that changes the Itesom* rate), 9-acid,
stannic acid, lead acid.

At least one partial or complete alkyl ester selected from the group consisting of zinc acid, umbilic acid, titanic acid, alkyl acid, and gemic acid can be used in combination.

Typical examples of these O alkyl esters include tetramethyl silicate, tetraethyl silicate, tetravirsilicate, tetramethyl V9 cate, tetraethyl germanate, tetravirgermanate, and tetrabutyl gel! Although nates can be preferably used, it is not necessarily limited to these, and 0 partial esters thereof may also be used.
The proportion of lucilicate and dopant material O in the alkali can be appropriately selected depending on the desired refractive index of the optical fiber base material and the type of the material, and is not particularly determined.

In the present invention, an alkyl silicate such as the above-mentioned methyl silicate) and methyl alcohol are used.
□ Mix alcohol such as sol O at a volume ratio of 1:9, add water to hydrolyze it, and sol-form solution II (7
9 force sol i1m) is produced, and this sol-like solution is
60cc@lj, and then! Atmospheric pressure [fl compressed gas per minute 1611! f01F16 are respectively supplied to the spray nozzle and sprayed from the tip of the spray nozzle as 11 to go sol droplets in size.At this time, the compressed gas is O such as argon.
It is preferable to use an inert yxt and set the compressed gas pressure to 1 to S atmosphere. (a) When the pressure is increased, the diameter of the droplets becomes smaller, and the silica glass zero particle price to be produced becomes smaller. Inside the furnace core tube (heating zone dewm, atmosphere male supply row etc.)
Depending on K, ammonia (1401
) is supplied as an atmosphere gas at 10JI@degrees per minute.

wI! Air in the air is not necessarily necessary, but it is preferable to use it to promote gelation.The promotion effect is very hot if the ammonia is high, but 5 moles or more is sufficient. It is. Also, inside the core tube (heating zone) O
Temperature %100~1oaocoll! Although there are ants in the field, if the temperature is too high, esters in water or alcohol will remain, reducing the optical properties and mechanical properties (strength) of the products. On the other hand, it is high temperature and Hirobu club.

Therefore, it is optimal to set the maximum temperature in the furnace tube to a grain density of 100° C., thereby making it easier to obtain grains IK26-16P grain O1/su*ytus stem powder. In addition, if the above-mentioned sol-like **e viscosity is high, it will be difficult to form a Kll-like state during injection;
It is necessary that the size be 6m4 or less.

Furthermore, in the present invention, prior to storing O*m such as the above-mentioned aqueous water or alkyl ether, and melting the end of the nine-sintered filtrate to make it transparent, a hot part Il is carried out. It is preferable that the heat treatment conditions Hsoo to tsos°C0
It is appropriate to set the threshold to s6 minutes to 2 o'clock at 1LII.

(by O treatment), particle size 10 ~ t@apmlift) silica
aoot), the grain size is uniform, there is no burr, and it is possible to make fake grains.

Then %ζO powder was added by known method))
- It may be difficult to prepare the lath base material with a high degree of flame or plasma flame.

Next, the present invention will be explained with reference to the drawings.

Fig. m #i Honshu @K x Shishi force j Tsus powder O generation device 〇 - Please show a specific example.

The code 1 is the nor-like pressure supply port, and 2 is the sol-like supply port 5.
ill s is a sol-IIO storage container, 4 is a transport pipe,
i is a flow rate regulator, 6 is a jet nozzle, 1 is a vns*sx boat 0. @HiroEIIIX 11110.9 is a sol droplet,
1. Sister heating element, ll#i furnace tube, 1! 1 indicates the exhaust port, 1 ink indicates the 9iI Oras test end O storage container, and 4 indicates the S/Shica j tsus stem end.

The fly obtained by hydrolyzing kVν cate in alkali and stored in the sol-form casting liquid storage container i (S/9 sol-form IIIIE (S/9 Kasol IE) 1 is supplied from the pressurizing gas supply port 1).
*11E and is supplied into the injection nozzle 6 through the transport pipe 4. The sol-like solution @10 supply amount is adjusted by the flow rate regulator section).

A good sol 1[2a] is supplied into the spray nozzle 6.

At the same time as the 40gh end of the spray nozzle sprays, the pressure line -
(by compressed gas supplied from the IX supply port) into a mist 1
), Sol Kandrop! It is heated (by heating body 1e) and gelatinized in the nine furnace tubes 11 (heating zone), and the glass powder O storage capacity is 91 m.
You can get 9 yen and 14 yen in total. At this time, gas generated due to gelation and compressed gas ejected from the spray nozzle 4 are exhausted from the exhaust port 12.

The ζO produced in this way was melted and made into transparent vitrification by the above-mentioned known O7R method) and fed into a blown flame together with oxygen and hydrogen gas.

The 3111 melting of IIIkK in this large flame is carried out to produce transparent glass, and silica for single-party fibers is manufactured (III is omitted).

Next, the present invention will be explained in detail, but the present invention is not limited in any way, but 0''C is an umbrella.

Example 1 Tetotsumethylsilake) (5ii(0(%)*)
and methyl alcohol at a volume ratio of 1:! The mixture is mixed with water and hydrolyzed to obtain a sol-like solution, which is then treated with a suitable method (as shown in the drawing) to obtain S/9.
Good for generating Kagarasu powder.

That is, ζO sol state Ilt 100 dens per minute,! Atmospheric pressure O
Compressed argon gas is supplied to the injection nozzle 4 at a rate of 1.10 per minute, and the large @i! 110~@0part) Spray the sol droplet ``9'' into the spray nozzle from the tip. Furthermore,
Alpunganu containing Anne Air 54J11f- is supplied from the atmosphere gas supply lower at a rate of 1 g11e per minute to raise the temperature in the furnace tube 11 (heating zone) to the maximum #i.
As a result, Kml in the storage container 1z
i2.~l@pmO Gelled silica glass powder can be obtained.

Next, the usual method Kl! Yes, oxygen per minute 1@6j, hydrogen per minute 1@
・Blow out with j★Put 4a/1・f of the above y9 force j tsus powder into the flame, melt it at 1400 ~ ℃ 0 temperature, and obtain shi9iIj tsus, ζOshi*19
SuOII prayer rate tAtsubeMeasure with shoulder foldometer, t45
A value of 80 was obtained, and a value of 11 was obtained with 10 g # of glass used as the base material glass for party tethers.
picture.

Implementation f42 Tetofmethyl silicate (at(oaa)4) and tetramethylgermanate as dopant [G.(OO
Iils) a) and are mixed at a volume ratio of 9:10,
The 0fIIa compound and methyl alcohol were mixed in a volume ratio of 1:9.
The mixture was mixed with water, water was added thereto for hydrolysis, and a sol-like solution was obtained. A silica glass powder (particle size 2·~N Opm) was obtained.

Below, the melting and transparent vitrification temperature is 1190 to 1700℃.
A doped silica glass was obtained by the same IIO operation as in Example 1, except that: Refractive index of glass is Fi1.472
The refractive index of p1 quartz glass O (L458) is about 1 compared to K.
-1iIIL was high, and there were no bubbles in the mesh, which was uniform and could be used satisfactorily as an optical fiber dosing material glass.

Example S Same as Example 1 - depending on raw materials and operation), particle size 2u-5@p
Make mD dal and obtain nine shishikadalas powder.

Then, the resulting product is heat-treated at 1000C for about 2 hours to obtain natural quartz Kfil/%Si11 powder containing less water and alkyl esters.

Hereinafter, the operation was performed under O conditions as in the actual feeding, and the refractive index was t48.
Obtain a transparent 1/v*y las with value 01? No air bubbles were observed in the liquid, and the material could be used satisfactorily as a material for 7 eyelids.

As explained above, according to 1 Li@, silica glass powder of 1 particle size (10 to 10 g 1711) is produced, which is melted using a conventional method and turned into transparent glass to produce silica glass. Can be prepared at high speed. In addition, in order to produce silica glass powder from a sol-like solution, the two materials are combined at the molecular level by adding a type O dopant. 1kiichiot
k - Has a verdict of having a very homogeneous composition.

41111iO Brief Explanation The drawing is a schematic diagram showing one specific example of the i/licas glass oxide generator described in Book 11@.

1...Male supply port for pressurizing sol solution! ...Fist sol-like S* S...Sol-like solution 0IIL storage container 4...Transport tube algae...Flow rate adjustment-6...Spray-nozzle 7...Wll air β gas supply port 8...・Compressed gas supply port! ...Zohie! Drops 100...Heating body 110@・Furnace tube 12...Exhaust port 1s@1・V lycaglass powder*O storage container 14 fist・
Fist $−′ ψ Force t! [Patent applicant: Nippon Telegraph and Telephone Corporation]

Claims (3)

[Claims] (1) Hydrolyze alkyl silicate to form a sol*
*, the sol-like solution is sprayed into a heating zone (through a spray nozzle) to produce a silica gaff powder, and the silica gaff powder is then fed into a flame or gas flame to melt and turn into transparent vitrification. Features: A manufacturing method for a fiber optic I5. (2) Schiff M, tin al & lead acid, 1ueH, hou H, titanium II! as dopant materials to O alkyl silicate before hydrolysis! , alkinoic acid and dalminilamic acid) V Rika Gassu 0
Preparation method. (3) Request for permission to heat-treat the ends of the series before melting and turning them into transparent glasst) IE l!
# (1) or (2) O V9i for optical fiber
I Melas OJl construction method.